#include <iostream>
#include <vector>
using namespace std;

int main(){
	ios_base::sync_with_stdio(0);
	cin.tie(0);

	vector<int> v;
	unsigned n, x, i, c = 0, d = 0;

	cin >> n;
	for (i = 0; i < n; ++i){
		cin >> x;
		v.push_back(x);
	}

	for (i = 0 ; i < n; ++i){
		if (v[i] >= v[i+1]) c++;
		if (v[i] <= v[i+1]) d++;
	}

	if (c == n || d == n) cout <<"da";
	else cout << "nu";

	return 0;
}